The present invention relates to polymer dispersions which can be prepared using polymerizable polyalkylene glycol macromonomers.
The polymeric emulsifiers and protective colloids used for very diverse applications are generally ambivalent copolymers which contain both hydrophobic and hydrophilic comonomer fractions. A typical example is the partially hydrolyzed polyvinyl acetate used in the suspension polymerization of, for example, styrene, disclosed, for example, in W. P. J. Bailey in Chemistry and Technology of water-soluble Polymers, Plenum Press, 1983 page 261 et seq., ISBN 0306-41251-9, which adsorbs via the nonhydrolyzed fractions of vinyl acetate to the emulsified styrene droplets and, via the hydrophilic fractions of polyvinyl alcohol, ensures emulsification of these droplets in the aqueous suspension. Copolymers of acrylic acid and hydrophobic acrylic and methacrylic esters, such as, for example, dodecyl methacrylate, which are used in the cosmetics sector to formulate and stabilize aqueous lotions and emulsions of water-insoluble oils (lit: BF Goodrich product information xe2x80x9cPemulen Emulsifiersxe2x80x9d 1995), or acrylic copolymers, which are used to stabilize aqueous dispersions of silicates, gypsum, talc, clay and other minerals in the exploration of petroleum and formulation of building materials (EP-A-0 870784), act in a similar way.
JP-A-5-209 052 discloses copolymers of vinyl chloride with vinyl polyether macromonomers which are produced in the form of solid products. A dispersing action of the vinyl polyether macromonomers is not disclosed.
EP-A-0 736 553 discloses copolymers of carboxylic acids or derivatives thereof and propoxylated vinyl ethers, but these too do not form a dispersion.
The object of the present invention was to find a process with which copolymers can be directly obtained as aqueous dispersions.
The present invention describes a class of water-dispersed copolymers which can be prepared by copolymerizing allyl or vinyl polyethers with known, mostly hydrophobic monomers. The copolymers can be used without a diluent for the emulsification/dispersion, or, depending on the process and intended use, such as, for example, in the case of emulsion polymerization, can be prepared in situ by adding small amounts of the polymerizable macromonomers.
The invention thus provides aqueous dispersions preparable by polymerization of an olefinically unsaturated, water-insoluble compound in the presence of a water-soluble allyl or vinyl ether of the formula 1 
in which
b is 0 or 1
n is 0 or1
k is an integer from 1 to 20,
X is O or N[(Axe2x80x94O)mxe2x80x94R]
A is C2-C4-alkylene
m is an integer from 5 to 900, and
R is H or C1-C4-alkyl,
and in which A is not exclusively C3- or C4-alkylene, by mixing the olefinically unsaturated water-insoluble compound with the water-soluble allyl or vinyl ether in water, and triggering the polymerization by a free-radical initiator.
k preferably assumes values from 2 to 12, in particular 4 to 8. X is preferably oxygen. R is preferably hydrogen. In a further preferred embodiment n=1, b=0 and X=O.
In the alkoxy chain given by (Axe2x80x94O)m, A is preferably an ethylene or propylene radical, in particular an ethylene radical. The total number of alkoxy units is preferably between 8 and 240, in particular between 16 and 115. The alkoxy chain can be a block polymer chain which has alternating blocks of different alkoxy units, preferably ethoxy and propoxy units. It can also be a chain with alkoxy units in random sequence.
In a preferred embodiment, xe2x80x94(Axe2x80x94O)mxe2x80x94 is an alkoxy chain of the formula 
in which
a is a number from 0 to 300, preferably 1 to 80, in particular 2 to 35
b is a number from 5 to 300, preferably 8 to 80, in particular 10 to 45
c is a number from 0 to 300, preferably 8 to 80, in particular 8 to 35.
In a further preferred embodiment, xe2x80x94(Axe2x80x94O)mxe2x80x94 is an ethoxy radical having from 8 to 240 ethoxy units.
A common feature of all of the embodiments is that preferably at least 50 mol % of the radicals (Axe2x80x94O) are ethoxy radicals, in particular 60 to 90 mol % are ethoxy radicals. The number of propoxy and butoxy radicals is, in a preferred embodiment, at most so great that the cloud point of the compound of the formula 1 in water is still at 30xc2x0 C. or above.
If X is N[(Axe2x80x94O)mxe2x80x94R], then the compounds of the formula 1 have the following structure: 
The compounds of the formula 2, in which k, A, m, n, b and R are as defined above, are also provided by the invention.
The invention further provides compounds of the formula 1 in which X=O and R=C1-C4-alkyl. Preferably, in such compounds n=0.
The compounds of the formula 1 are also referred to below as polymerizable macromonomers.
The preparation of the polymerizable macromonomers, and illustrative applications of the dispersions according to the invention are described in more detail below and illustrated by reference to examples.
The polymerizable macromonomers are prepared by anion/alkali initiated polymerization of hydroxy- or amino-functional allyl or vinyl ethers (ethers which still have at least one active hydrogen atom) with alkylene oxide or mixtures of alkylene oxides in random distribution or as block copolymers. Furthermore, the resulting macromonomers can also be etherified at the terminal hydroxyl groups by means of a Williamson synthesis. The hydroxy- or amino-functional allyl or vinyl ethers have formula 3 
where Y=OH, NH2.
The degree of water solubility, defined by the cloud point, of the polymerizable macromonomers, and the extent of their hydrophilicizing and dispersing action can be set by the ratio and number of alkylene oxide units, preferably of ethylene oxide to propylene oxide, and through the choice of the hydroxy- or amino-functional allyl or vinyl ether.
The free-radical initiated copolymerization of the polymerizable macromonomers with olefinically unsaturated water-insoluble monomers produces the copolymer dispersions according to the invention. Suitable water-insoluble monomers which can be polymerized with the macromonomers are, for example, the following:
vinyl monomers, such as carboxylic esters of vinyl alcohol, for example vinyl acetate, vinyl propionate, vinyl ether of isononanoic acid or of isodecanoic acid, styrene and stilbene,
olefinically unsaturated carboxylic esters, such as ethyl acrylate, n-butyl acrylate, i-butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, and the corresponding methacrylic esters,
olefinically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid and itaconic acid and their sodium, potassium and ammonium salts,
olefinically unsaturated sulfonic acids and phosphonic acids and their alkali metal and ammonium salts, such as acrylamidomethylpropanesulfonic acid (AMPS) and its alkali metal and ammonium, alkylammonium and hydroxyalkylammonium salts, allylsulfonic acid and its alkali metal and ammonium salts, acryloyloxethylphosphonic acid and its ammonium and alkali metal salts, and the corresponding methacrylic acid derivatives,
olefinically unsaturated amines, ammonium salts, nitriles and amides, such as dimethylaminoethyl acrylate, acryloyloxethyltrimethylammonium halides, acrylonitrile, N-methacrylamide, N-ethylacrylamide, N-propylacrylamide, and the corresponding methacrylic acid derivatives and vinylmethylacetamide,
olefins, such as ethylene, propene and butenes, pentene, 3-butadiene and chloroprene,
vinyl halides, such as vinyl chloride, vinylidene chloride and vinylidene fluoride.
The present invention further relates to the use of the above-defined macromonomers of the formula 1 in emulsion polymerizations or suspension polymerizations.
The invention further provides for the use of the polymerizable polyalkylene macromonomers according to the invention as emulsifiers or dispersants.
The compounds of the formula 1 can be used in suspension or emulsion polymerizations alone as emulsifiers, and also in a mixture with anionic and/or nonionic surfactants known in the prior art.
Customary anionic surfactants are sodium alkyl sulfate, sodium dodecylbenzenesulfonate, sodium alkylsulfonate, sodium and ammonium alkylpolyethylene glycol ether sulfates, sodium and ammonium alkylphenol polyethylene glycol ether sulfates, and alkylpolyethylene glycol ether phosphoric mono-, di- and triesters and mixtures thereof, and alkylphenol polyethylene glycol ether phosphoric mono-, di- and triesters and mixtures thereof.